Need help - rough idle and bogging out

[citmov]

I've had my car in storage for 4 months - started it up every 3 weeks and it ran smooth. no issues whatsoever. i just brought it home and now i've got the roughest idle to the point where it sometimes kills the engine, rpm's are everywhere, and the motor is just shaking.

here's a vid of exactly what it's doing:
YouTube - rough idle

here are my specs:
1990 GT - stock 5.0
recently replaced: plugs, wires, cap, rotor, EGR valve, idle air control sensor, fuel pump, hanger, filter, and fuel injector cleaner.

any suggestions? i'm not that mechanical so any help would be appreciated. lastly, i recently took apart my interior to change out my carpet. i did pull the console, radio, glove compartment and some other minor parts of the dash (ie. vents, bezzel) but i didn't pull anything major. right after this it started happening. please help me if you can. thanks!!!


---
Hahn
1990 GT

 

[Burlyirishdude]

well its good you have oil pressure. That rpm needle is moving like something isn't connected right on instrument panel.

I would check to make sure all your spark plugs have the wires pushed on them all the way. If the motor is vibrating i assume, somethings not getting one of three things, "Comp, Spark, Fuel" when making assumptions about engine shaking i guess misfire/nofire.

For idle issues i start at the bottom and work my way up....
Good gas? New fuel filter? start with the simple check stuff, gas/vacuum lines/sensors all hooked up. I know it sounds stupid but you'll save time if you check the easy/small stuff first. then start working the specifics.

hope you figure it out....nothing worse then a lame horse.

 

[FriscoSteve]

If you lightly tap on the IAC with a screwdriver, does the idle change at all? If the rpms change at all up or down when you tap it, perhaps its a stuck IAC. I would try to clean it first before replacing it.

 

[HISSIN50]

I would run a cylinder balance test.

 

[FriscoSteve]

Hahn, did you get it sorted out?

 

[Tanus]

looks like an ignition problem, the way the tach needle jumps real quick

 

[citmov]

Thanks everyone for taking the time to help me out and for all your input. Really good stuff. But as of now I still haven't figured it out yet. I took a break from it today b/c I spent all day yesterday trying to figure it out not to mention the crappy weather out here in Chicago (cold and rainy). Not sure where to go from here.

-I don't think it's the IAC as I already replaced that as well as the EGR valve.

-If it's an ignition problem how do I need to do?

-I wish I knew how to run a cylinder test. what is that?

Someone mentioned that it might be 2 other things:
(1) sugar in my gas tank
(2) a bad fuel pressure regulator
What do you guys think?

Any other thoughts?

I'll work be back working on the stang tomorrow rain or shine. Thanks again for all the advice. I can change plugs/wires/cap/rotor but I'm not as tech savvy as you guys so I really appreciate your advice and time.

---
Hahn

 

[HISSIN50]

Your repair manual should have instructions on the CBT. Here's a synopsis as well.

 

[citmov]

one more thing to add...
is there anything by the radio, under the steering wheel, under the seats, under the console, or anything under the side kick panels that could've made my engine/idle do what it's doing? a switch? connector? anything? reason why i'm asking is b/c that's the only thing i touched before this all started happening. i'm so frustrated!!! if you guys have no other suggestions i may have to resort to bringing the car in. thanks again!


--
Hahn

 

[double3zero]

i would say bad gas i had the same prob with my outboard motor, 3 days ago it was running good in my yard. when i took it out the thing started boggin out the ethonal in the gas seperated and didnt wanna run on it i drained all gas and replaced the fuel filter and is running like new again. gas has only been in tank since 12/09 but thats all it takes for this new age gas to go bad i even had fuel conditioner and stabler in it

 

[MustangLX-5.0]

in the synopsis, it notes "Briefly depress the accelerator to WOT and release" . This is wrong. you don't do a quick WOT, you should only very lightly press the throttle about 10% of the way, and then release. You will know it's in the balance mode because the idle speed will hold, then raise up a little right after you release the throttle.

i don't think it's bad gas. I KNOW what bad gas can do and how it runs. My 92 was sitting around for years with crappy gas in the tank. I only added a little gas every other month and started it to keep
the gas from getting too bad. Bad gas will clog up the injectors and make them stick. It will miss bad and the plugs will get fouled up with gas quickly.

When your engine isn't screwing up, it seems to be running well. No missing or anything. It looks to be more like an ignition problem, especially with the way that tach flicks around like that.

 

[FriscoSteve]

So you thinking a timing issue then?

 

[citmov]

ok guys!...got it figured out. it was a bad IGNITION CONTROL MODULE.

so MustangLX-5.0, you sent me in the right direction. right on!

thanks everyone for all your help/suggestions! now i know the symptoms of a bad IGNITION CONTROL MODULE.

 

[MustangLX-5.0]

Wasn't just my idea.. Glad you got it figured out. Now, if only I could get mine figured out. It's driving me insane. Thing will not start for the life. It went from running.. to running badly.. to stalling.. and then finally no start at all. Maybe someone could take a look at my code 96 and code 66 threads. I didn't label the threads properly. And I ruled out those codes as being an unplugged MAF sensor a couple times, and constant stalling causing the 96.

 

[citmov]

ooops... credit to Tanus as well! my bad!

 

[Tanus]

haha thanks always glad to help